1. Field of the Invention
The present invention relates to a batch processing method for forming a structure including an amorphous carbon film on target objects, such as semiconductor wafers, in a semiconductor process. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target object, such as a semiconductor wafer or a glass substrate used for an FPD (Flat Panel Display), e.g., an LCD (Liquid Crystal Display), by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target object.
2. Description of the Related Art
In relation to the process of manufacturing semiconductor devices, inter-level insulating films with a low dielectric constant have been developed to further decrease the resistance or capacitance of interconnecting structures. An amorphous carbon film can be used as an inter-level insulating film with a low dielectric constant. Further, in the process of manufacturing semiconductor devices, plasma etching is performed to form a circuit pattern by use a photo-resist mask patterned by a photolithography technique. In recent years, owing to the demands of miniaturization of semiconductor devices, the thickness of photo-resist films is becoming increasingly smaller. Accordingly, it has become difficult to ensure a sufficient etching resistance only by a photo-resist film. In light of this problem, a pattern duplication technique has been proposed by utilizing a multi-layered resist structure (for example, see Jpn. Pat. Appln. KOKAI Publication No. 2006-140222). For example, a multi-layered resist structure is formed of a lower layer, an intermediate layer, and an upper layer (photo-resist film). An amorphous carbon film can be used as the lower layer of such a multi-layered resist structure.
Where an amorphous carbon film is applied to this purpose, the film is typically formed by plasma CVD (Chemical Vapor Deposition) of the single-substrate type (for example, see U.S. Pat. No. 5,981,000). The apparatus disclosed in this publication is a plasma CVD apparatus of the parallel-plate type configured to form a film by generating plasma inside a chamber while supplying a cyclic hydrocarbon gas into the chamber.
In general, where plasma CVD apparatuses of the single-substrate type are used to form a thin film, the coverage performance of the film tends to be insufficient. Accordingly, it has been studied to form an amorphous carbon film by use of an apparatus that can provide good coverage performance, such as a vertical CVD apparatus of the batch type. However, as described later, the present inventors have found a problem such that, where vertical CVD apparatuses are used to form an amorphous carbon film, the film tends to be deteriorated in surface flatness.